Russian mini tubes

[spongebob]

After reading Slajeunes experiments with 12V tubes I ordered a handful of russian subminiature tubes last week, and finally received them today. Now I need some help, here is a piece of the datasheet (tubes are 1Sh18b):



From my *very* limited knowledge of tubes, this are pentodes, right? Can I use these in the Ruby Tuby circuit for example? Because I remember reading somewhere that you can wire pentodes as triodes somehow...?

The cathode/filament calls for 1.2V, is it ok to use a 1.2V battery here and a different power supply (wall wart) for the rest of the circuit?

Any help appreciated!

[slajeune]

Hi Spongebob,

interesting tube!  Here is pretty much the only schematic that I could find:

http://www.jogis-roehrenbude.de/Leserbriefe/Jochens-2kreiser/Jochen-2kreiser.htm

This site seems to have a lot of low voltage tube stuff.  Unfortunately, I don't speak german....

For the heaters on a 1.2v battery, it depends on how much current it sucks.  If it does suck a bit of current, your battery might die very quickly!

My guess would be that you could use it in a ruby tuby setup.  Check out Doug's pentode driver for an example of using pentodes in pedals!

Cheers,
Stephane.

[spongebob]

Here is pretty much the only schematic that I could find:

http://www.jogis-roehrenbude.de/Leserbriefe/Jochens-2kreiser/Jochen-2kreiser.htm

There's an amplifier schematic on the same site which uses 1Sh18B (and 1Sh29B):
http://www.jogis-roehrenbude.de/Leserbriefe/Drehko-Stefan-Miniamp/Miniamp.htm

In the meantime I built the following on stripboard (taken from the schematic shown on the page above):


I can hear the guitar when I connect the circuit to my lm386 amp, but there's also a loud high-pitched whining tone, looks like I built an oscillator! :wink: The 15V are coming from a switch-mode power supply, but I don't think that should be a problem? The 1.2V for the cathode are coming from a battery, measured current draw is 23mA, that's not too bad. I'll recheck everything tomorrow, maybe it's just a wiring error...

[@ndy]

2 Spongebob:

Hi, I'm a newbie in this forum and I'm Russian. Just watched 1Sh18B datasheet, it seems to be high-frequency pentode. Max. plate current is 1.85 mA. I have seen such tubes in older military tranceivers.  Why not to try it in some preamp stages  :wink:  Try it in triode mode. If you need some more datasheet information about this tube I would be glad to translate it to you.

The high-pitched whining tone you mentioned might be an osscilation    Try to put 1nF capasitor in parallel to plate resistor.

Is 15V plate voltage sufficient for the tube? Normal datasheet value is 60V...
Good luck in your research.

[Peter Snowberg]

Welcome to the forum @ndy.

Spongebob, that oscillation you hear could easily be your switching supply. Try @ndy's suggestion of adding a 1nF cap across the plate resistor. If you don't hear a change in the frequency, chances are very good the supply is the source of the noise.

You could also try connecting the +15V line to the output via a small cap like 10nF. If the sound is in the power supply, that should show it to you.

Best of luck!
-Peter

[Lonestarjohnny]

Hi Andy,Welcome to the Forum.
JD

[Mr.Huge]

You guys should also check out the Nuvistor!
These were used in some old Ampex preamps. They’re pretty cool.

Nuvistor

Also see;
http://semiconductormuseum.com/OralHistory/RCA/Mendelson/Mendelson_Index.htm

http://www.logwell.com/tech/components/nuvistors.html

http://hhscott.com/cc/nuvistors.htm

[spongebob]

Hooray, it works! I replaced the power supply with two 9V blocks (18V) and the oscillation is gone. Looks like the switch-mode supply was causing the trouble. Output is now loud and clear (no distortion yet  :wink:), really amazing for a battery operated tube! I also tried using a single 9V battery, but the output level went down drastically.

My DMM shows only a very small current consumption on the two 9V batteries, like 0,06 mA, is this possible? If this is true, one could very well construct a battery-operated tube pedal... Did I mention that this tube is cheaper than a JFET transistor?  :lol:

@ndy: Welcome, and thanks for your help. I used babelfish.altavista.com to translate single words of the datasheet, for example I now know that aнoдe = anode, напряжение = voltage and Ток = current   Can you post a few of the other cyrillic words (and their english translation) that appear on this datasheet for example?



Thanks a lot!

[puretube]

yes switching PS can be a PITA, if you`re not aware of it - especially when dealing with clocked FX.
better to always put some xtra filtering between PS and FX.

[Ge_Whiz]

Yes, HT current consumption will be very low, and a couple of PP3 batteries will last a long time. Filament supply is the opposite; use a big D-size cell, or possibly even two in parallel. You'll be changing the filament battery several times in the lifetime of the 'HT' supply.

[@ndy]

Hi again!

I tried to translate some words as you've requested:



Sorry, I don't know all the special tube terms in English (like this S-value), but please ask if something is needed to be explained  

Andrei

[@ndy]

Heh... The picture is loading a bit too slowly  

[slajeune]

Hi All,

here is another link to a datasheet for this little tube (with loadlines!!!):

http://klausmobile.narod.ru/td/data/_1j18b.GIF

Steph.

[@ndy]

spongebob:

Inspired by your idea of experimenting with micro tubes, I searched for some concerning information in russian-languaged internet. Such tubes seem to be a favourite choise of Hi-End guru. Russian DIYers make low noise Hi-End DACs using pentodes of series 1sh... in triode mode. They call this series one of the most noiseless in the world. The disadvantage is that we have to insulate such tubes from vibration, because their filaments have their mechanical resonance somewhere close to 2kHz and there is a risk of microphonic effect.
I have couple of 1sh29b and will try to experiment too

Andrei

[spongebob]

Andrei, thank you very much for the translations!

Russian DIYers make low noise Hi-End DACs using pentodes of series 1sh... in triode mode.

What do you mean by triode mode? I have read this a couple of times elsewhere, how can I use a pentode as a triode?

I also got four 1Sh24b, they look identical to the 1Sh18b but have two more connections, one for the screen and one for the top grid I think...

Is it ok to increase the anode resistor to get the voltage at the anode down? Because with the 47K resistor (see above), the output at the anode measures around 13V (with 18V supply voltage), doesn't that seem a little bit too high? I replaced the resistor with a pot and found that the voltage drops to 9V with a resistance of 300k. Is this approach ok?

When building an overdrive pedal with these tubes, I don't think two stages have enough gain for some serious distortion, maybe putting a JFET gain stage in front of it would be a good idea? Something like this:

Jfet stage -> Tube Stage -> Volume Pot (Gain) -> Tube Stage -> Volume Pot :?:

Thanks for all the help!
Jan

[puretube]

triode-mode:

screen-grid tied to plate;

i.e.: screen grid directly connected to the anode,
instead of an extra fixed HT (or OT-tap).

gives less power, but more warmth...

[Peter Snowberg]

Here's a link that covers using the 1SH29B in single ended 12V and uses a 320 ohm resistor to ballast the filament.

http://www.midnightscience.com/_pdffiles/aren%20van%20waarde%20may%202003.pdf

It also mentions the use of a 220V -> 9V 2.4VA transformer as an output transformer. I've heard different things about the results of this approach esp. when it comes to bass but at such a small wattage maybe things don't matter as much.

More stuff here: http://www.b-kainka.de/roehren/roehren2.htm

Does anybody know where these tubes can be purchased in the west?

Thanks!
-Peter

[puretube]

maybe smallbear can get some?  :wink:

[Ansil]

try searching ebay. they have a butt load of subminiatures   i recently got some for a mini plexi i am doing.

http://search.ebay.com/subminiature-tubes_W0QQsokeywordredirectZ1QQfromZR8

[Ansil]

http://www.wps.com/archives/tube-datasheets/Datasheets/Raytheon-SP-7073-360-20M/2.JPG
this is a nice little datasheet to print out and keep for your bench so if you spy some cool tubes you can snatch them up.